Before Islamic State (also known as ISIS) fighters descended on Sinjar, Iraq in August 2014, the area was home to 360,000 Yezidis. Today, at least 90 percent of the Yezidi population has been displaced, after fleeing an ISIS onslaught that killed between 2,000 and 5,500 Yezidis. Additionally, ISIS fighters abducted an estimated 6,300 Yezidis and even forced their women and girls into a system of organized rape and sexual slavery.

Now, Iraqi forces have reclaimed the territory it lost to ISIS. And while Iraq's judges have been charging thousands of ISIS suspects, according to over a dozen lawyers and judges involved in the trials of ISIS suspects, there are almost no known trials specifically for crimes committed against Yezidis.

ISIS suspects are primarily being charged for ISIS membership, support, sympathy, or assistance under a vaguely worded counterterrorism law, and trial judges are primarily relying on a defendants' confessions, rarely requesting other evidence. This even happened after Iraqi forces freed a Yezidi girl from ISIS in March. Her captor was apparently also charged under counterterrorism law, instead of under the crimes perpetrated against her.

One outcome of these rushed trials is hundreds of problematic convictions and death sentences against alleged ISIS suspects.

Another outcome is that besides some local efforts, including those led by the Commission for Investigation and Gathering Evidence (CIGE) in Dohuk, sites of ISIS's crimes are not being investigated and authorities are not showing urgency to protect dozens of mass graves. Evidence of ISIS crimes is being lost to time.

The crimes committed against Yezidis amount to war crimes and may even rise to crimes against humanity or even genocide. But how can this be proven without evidence?

Additionally, the opportunity for Iraqis to know what really happened based on evidence is slipping away.

Since 2016, Yazda, a nongovernmental organization supporting the Yezidis, has identified at least 40 mass gravesites where Yezidi victims have been buried. Yazda's staff only know of up to three sites where exhumations may have occurred.

ISIS victims have repeatedly asked me why most of the mass graves are still unexhumed, and why evidence of such horrific crimes is not being preserved? They want their day in court, and they want to know where their loved ones are buried. Having driven through Sinjar and seen a landscape strewn with mass graves, all I can do is hope that on this four-year commemoration of the attack, authorities will redouble their efforts to protect and exhume these sites.